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When choosing a proxy codec, you want to go for one that does not use temporal compression (aka inter-frame compression or long-GOP compression), and you want to pick one that has a lower bitrate. The low bitrate means that the files are much smaller, so you can use fewer/smaller/cheaper hard drives, simplifying your workflow.
By far the most common proxy codecs are DNxHD/DNxHR and ProRes. They have both been around for years, so they’re very widely supported. Everyone knows how to handle them. They are both very well suited to a proxy workflow (ProRes even has a preset called “proxy”), and are nearly interchangeable when used for proxies.
Since DNxHD is made by Avid, and ProRes is made by Apple, it makes sense that DNxHD would work better on Media Composer and ProRes would work better on Final Cut Pro X. That used to certainly be true, but nowadays both codecs work very smoothly on all modern editors (including Premiere Pro and Resolve). There may be a slight speed increase in using the codec that was designed for the system, but it’s very slight.
The only significant difference between the two for a proxy workflow is the fact that you may have trouble creating ProRes on a PC, while DNxHD is very easy to create cross-platform. PCs can easily play back and edit ProRes files, but you can’t encode new ProRes files on a PC as easily as DNxHD, and so some editors prefer a DNxHD workflow for that reason.
A third good option is Cineform, which was acquired by GoPro but is still supported by all of the creative tools. Cineform offers similar options to DNxHD and ProRes, and it has shown slightly better image quality in some tests, but not by a huge amount.
Regardless of which of the codecs you pick, you also have to pick which flavor you want. This is really going to depend on your storage constraints – it’s a tradeoff between image quality and file size. The good news is that you don’t need tip-top image quality when you’re editing, so you can choose a low-bitrate codec.
Start off with the smallest ProRes or DNx codec in the same resolution as your capture codec. Look at the GB/hr column and multiply it by the number of hours of footage you have. If you have enough storage space, then you’re good – use that codec. If you have lots of extra storage space, think about using the next largest flavor.
If you don’t have enough storage space, or if you’re on an underpowered machine, then take the resolution down a notch. A lot of huge-budget Hollywood films were edited in 480p just a few years ago, so don’t sweat it if you need to lower your resolution from 4K down to 720p for the edit.
Of course, you always want to edit with decent-looking footage, but it can be hard to estimate which codecs and bitrates provide the clearest image. Check out the Codec Comparison to see how different codecs impact image quality.
Video collaboration solved.